Method for die casting an inner door panel for a vehicle side door

ABSTRACT

A method for manufacturing an inner door panel for a vehicle side door that employs a die casting process. The method includes providing a die cast mold having opposing mold halves that combine to define a die cavity configured to provide the inner door panel. An impact beam is positioned in the mold cavity prior to combining the first mold half and the second mold half, and a molten metal is provided to the mold cavity so that molten metal flows into all areas of the mold cavity and around the impact beam after the first mold half and the second mold half are combined. A solidified molded inner door panel is then removed from the die cast mold that includes an encapsulated impact beam.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional application of U.S. patent applicationSer. No. 14/096,527, filed Dec. 4, 2013, titled “Integration of OnePiece Door Inner Panel with Impact Beam”.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to a method for manufacturing an innerdoor panel of a vehicle side door and, more particularly, to a methodfor manufacturing an inner door panel of a vehicle side door thatincludes die casting the inner door panel with an impact beam as asingle integrated cast.

2. Discussion of the Related Art

Much engineering goes in to the design and manufacture of vehicle doors.A typical vehicle side door will include an outer door panel oftenformed of stamped steel, an inner door panel also formed of stampedsteel and a trim panel. An impact beam is typically bolted or welded tothe inner door panel so that it is between the inner door panel and theouter door panel for providing protection against side impact. Also,various reinforcement members are often welded to the inner door panel,such as a latch reinforcement member, a hinge reinforcement member and awaist reinforcement member. Once the reinforcement members and theimpact beam are mounted to the inner door panel, the outer door panel isthen secured to the inner door panel by folding over and joining an edgeof the outer door panel to the inner door panel in a hemming process toprovide a door in white. The inner trim panel is then mounted to theinside surface of the inner door panel. The various door hardware, suchas window switches, motors, latch mechanisms, wiring, etc., areassembled at the appropriate time during the assembly process. Althoughthe inner door panel, the outer door panel, the impact beam and thereinforcement members are typically made of steel, some or all of thesecomponents have been known to be made from other materials such asaluminum and polymers.

Die casting is a known metal forming process where a molten metal in aliquid state, such as aluminum or magnesium alloys, is poured orotherwise caused to flow within a die cavity defined by opposing diehalves and cooled to be solidified therein to form the particularcomponent. During the casting process, the die halves are clampedtogether and the molten metal is caused to flow through an orifice intothe die under high pressure via a plunger through a shot-sleeve. Oncethe molten metal has solidified, the die is opened and the now hardenedpart is removed.

Die casting offers a number of advantages over stamping, forging andother metal forming processes including the ability to form highlycomplex or intricate part, simplified design and manufacturing andassembly processes, better quality, higher productivity due to a nearnet-shape process, etc. However, in order to allow a particular part tobe die cast, it is necessary that the configuration of the part be suchthat all areas of the die cavity be filled with molten metal to form thepart and allow the die halves to be separated without interference fromthe part.

SUMMARY OF THE INVENTION

In accordance with the teachings of the present invention, a method formanufacturing an inner door panel for a vehicle side door is disclosedthat employs a die casting process. The method includes providing a diecast mold having opposing mold halves that combine to define a diecavity configured to provide the inner door panel. An impact beam ispositioned in the mold cavity prior to combining the first mold half andthe second mold half, and a molten metal is provided to the mold cavityso that molten metal flows into all areas of the mold cavity and aroundthe impact beam after the first mold half and the second mold half arecombined. A solidified molded inner door panel is then removed from thedie cast mold that includes an encapsulated impact beam.

Additional features of the present invention will become apparent fromthe following description and appended claims, taken in conjunction withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified illustration of a die cast mold;

FIG. 2 is an isometric view of an inner door panel for a vehicle sidedoor that has been die cast using the mold shown in FIG. 1 and includesan integrated impact beam and a gate runner and overflow system;

FIG. 3 is an isometric view of the inner door panel shown in FIG. 2without the gate runner and overflow system; and

FIG. 4 is a simplified cross-sectional view of an inner door panel thathas been die cast around a separate impact beam.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following discussion of the embodiments of the invention directed toa technique for manufacturing an inner door panel of a vehicle side doorwith an integrated impact beam using a die casting process is merelyexemplary in nature, and is in no way intended to limit the invention orits applications or uses.

The present invention proposes a die casting process for fabricating aninner door panel for a vehicle side door, where the inner door panelincludes an integrated impact beam. As discussed above, a typicalmanufacturing process for a vehicle side door requires an assemblyprocess for the inner door panel of several different door partsincluding welding various reinforcement members to the inner door panel,such as a latch reinforcement, a hinge reinforcement and a waistreinforcement, and bolting or welding an impact beam to the inner doorpanel. In the die casting process of the invention, all of thosecomponents are integrated into a single cast structure formed in a diecasting mold. Those areas of the inner door that require reinforcement,which previously had been provided by the separate reinforcementmembers, can be made by providing a thicker section or a more robustarea with embedded reinforced features in the die cast mold where moremolten material is provided.

By employing a one-piece casting process for manufacturing the innerdoor panel, a reduction in design complexity, manufacturing cost andcycle time is provided. Further, the die casting process generates alighter weight structure as compared to the stamped inner door panel andouter door panel assembly known in the art. Also, the manufacturing andassembly process for the vehicle door using the die casting process ofthe invention provides a reduction in cost as a result of a simplifieddesign and manufacturing/assembly process, and a reduction in materials.Further, because the die casting process employs a single material toform the entire inner door panel structure, there are no issues withgalvanic corrosion as a result of mixed materials.

FIG. 1 is an isometric type view showing a simplified illustration of adie cast mold 10 including a first mold half 12 and a second mold half14. The mold 10 includes an inner cavity 16 that is shaped to theparticular component being manufactured, here an inner door panel for avehicle side door, and provides the necessary runners and gates thatallow the molten metal to easily flow to all areas in the cavity 16. Anopening in the mold 10 when the mold halves 12 and 14 are clampedtogether allows access to the cavity 16 so that a molten metal from, forexample, a shot-sleeve, can flow into the cavity 16. Although the metalcan be any metal suitable for the purposes described herein, typically adie cast vehicle door panel will be aluminum or magnesium alloys. It isnoted that the process for insuring that the molten material enters allof the open areas in the cavity 16 can be provided by suitable pressureand velocity. In the embodiments being discussed herein, the die castprocess employs a vacuum-assist process to improve fluidity of the meltand hence reduce porosity in the finished part. Further, suitablecooling channels (not shown) can be provided within the mold 10 toreduce the temperature of any hot spots that may affect fabrication ofthe inner door panel as discussed herein.

FIG. 2 is an isometric view of an inner door panel 30 fabricated by adie casting process of the invention after it has been removed from themold 10, but prior to when certain runners, gatings, overflow pieces,etc. have been removed by a suitable severing process, such as trimming,as would be well understood by those skilled in the art. FIG. 3 is anisometric view of the inner door panel 30 after the runners, gatings,overflow pieces, etc. have been removed showing the final door panelshape and design.

The inner door panel 30 includes an outer frame 32 that encircles theentire inner door panel 30 and defines a central opening 34 therein. Theouter frame 32 includes a number of structural elements and parts thatcombine together and define the shape and configuration of the innerdoor panel 30 for a particular vehicle design to provide the desiredstructural integrity and weight. In this non-limiting design, the outerframe 32 includes a top rail 38, a bottom rail 40, an inner side rail 42and an outer side rail 44. The top rail 38 includes a series ofreinforcement ribs 48 extending along the top rail 38, for example, in azig-zag configuration as shown. The inner side rail 42 includes a raisedportion 50 and a lower portion 52 defining a vertical wall 54therebetween. A planar portion 56 extends from the lower portion 52 anddefines an opening 58 that is configured to accept a window motor orother door hardware. A side light support member 60 extends from theupper rail 38 proximate the planar portion 56. A support portion 62 isprovided at the corner where the lower rail 40 and the outer side rail44 meet.

The inner door panel 30 is die cast with an integral side impact beam70, which provides reinforcement for side impacts to the vehicle. Theside impact beam 70 includes a main beam 72 that extends across theopening 34. The impact beam 70 also includes a first support end 74having a configuration that allows it to be integrally formed with theside rail 42 so that it is coupled to the vertical wall 54 and the lowerportion 52 as shown. The support end 74 includes a series of spacedapart ribs 76 that provide the desired structural integrity with reducedmaterial for reduced weight. A second support end 78 of the impact beam70 is formed as part of the support portion 62 and also includes spacedapart ribs 80 that provide structural integrity in a light weightmanner.

As is apparent, most of the outer frame 32 is along one plane and theside impact beam 70 is raised relative thereto to be positioned along aseparate plane. Traditionally, such a configuration of a part wouldprevent the part from being made as a single piece unit in a die castingprocess. Particularly, because the die cast mold is formed from twohalves where joining the halves defines the cavity in which the part ismolded, attempting to die cast parts having components on separateplanes with space therebetween presented issues of being able toseparate the mold halves once the part had harden within the moldcavity. The present invention overcomes this limitation by providing thecentral opening 34 so that the location of the beam 70 is adjacent andrelative to open space to allow portions of the mold halves 12 and 14 tocontact each other where the opening 34 will be located to die cast thecomplete inner door panel 30.

When designing a die cast mold, it is often necessary to provide moltenmetal runners within the die cavity that optimize the filling andestablish sequential solidification of the molten metal in all areas ofthe cavity 16. As such, the mold cavity 16 includes cavity portions andchannels through which the molten metal flows and that form a runner andgating system 90 when the part has solidified that captures how themolten metal flows to the mold cavity portions that form the outer frame32 and the impact beam 70, and also allows the mold halves 12 and 14 tobe separated after the inner door panel 30 has solidified within themold 10. The discussion below describes the runner and gating system 90as being the structural elements that are part of the die cast part whenthe molten metal solidifies within the mold 10. It is noted however thatthe actual runner and gating system is the cavity portions within thecavity 16 that allows the molten metal to travel to those areas in themold cavity 16 that form the inner door panel 30.

The gating system 90 includes a molten metal entry point 92 where themolten metal is introduced into the mold 10 that is connected to a mainrunner 94 which branches out to be connected to side runners 96 and 98.The side runner 96 connects to a plurality of downwardly extendingvertical runners 100, here five, that form the impact beam 70. Thegating system 90 also includes a plurality of runners 102, here four,that provide molten metal to the lower rail 40. The side runner 98connects to a plurality of horizontal runners 104 that provide themolten metal to the top rail 38, the planar portion 56 and the outerside rail 44. All of the runners are carefully designed in size,orientation and configuration so that when the molten metal enters theentry point 92 it flows through the runners to provide a uniform fillingpattern with low gas entrapment to form the inner door panel 30. Aplurality of overflow channels in the mold cavity 16 extend around thecavity portions that define the outer frame 32 and allow front melt toflow therein and form overflow pieces 108, here twenty-six, whichusually contain some products of oxidation and any excess lubricant thatis wept away.

Once the inner door panel 30 is removed from the mold 10 as shown inFIG. 2, all of the formed runners are trimmed to define the final diecast inner door panel 30 as shown in FIG. 3. Thus, it will be apparentto those skilled in the art, that the two mold halves 12 and 14 can beclamped together so that the cavity 16 therein defines all of thestructural elements shown in FIG. 2 and allows solid parts of the twomold halves 12 and 14 to contact each other at the open areas around andbetween the parts in the opening 34.

During the die casting process, steel bands or supports can be mountedin the cavity 16 for the impact beam 70 to increase its impactdurability.

In an alternate cast-in-place embodiment, an impact beam is placed inthe cavity 16 of the die cast mold 10 and the molten material is pouredinto the mold 10 so that it flows around the impact beam. A speciallychosen coating could be applied on a surface of the pre-placed impactbeam in order to control interface bonding and reactions between themolten metal and the impact beam.

FIG. 4 is a cross-sectional view showing an inner door panel 110 afterit has been die cast to illustrate this embodiment. In this embodiment,a more traditional shape for an inner door panel for a vehicle side doorcan be provided where the central opening 34 can be eliminated and metalcan be provided across an entire plane of the door panel 110. Byconfiguring the cavity 16 in the mold 10 to allow an impact beam 112 tobe positioned therein the molten metal will flow around an outsidesurface of the impact beam 112 to form an extended panel portion 114relative to a base panel portion 116 and the mold halves 12 and 14 canbe readily separated without concern for open areas between the impactbeam 122 and the plane of the inner door panel 120. Further, this allowsthe impact beam 122 to be made of a different material, such as extrudedaluminum alloys, magnesium, and hot stamped steels, and the inner doorpanel can be made of another material, such as magnesium.

The foregoing discussion discloses and describes merely exemplaryembodiments of the present invention. One skilled in the art willreadily recognize from such discussion and from the accompanyingdrawings and claims that various changes, modifications and variationscan be made therein without departing from the spirit and scope of theinvention as defined in the following claims.

What is claimed is:
 1. A method for die casting an inner door panel fora vehicle side door, said method comprising: providing a die cast moldincluding a first mold half and a second mold half each including acavity that combine to provide a mold cavity, said mold cavity beingconfigured to form the inner door panel; positioning an impact beam inthe mold cavity prior to combining the first mold half and the secondmold half; providing a molten metal to the mold cavity so that moltenmetal flows into all areas of the mold cavity and around the impact beamafter the first mold half and the second mold half are combined; andremoving a solidified molded inner door panel from the die cast moldthat includes an encapsulated impact beam.
 2. The method according toclaim 1 further comprising applying a coating on a surface of the impactbeam prior to positioning the impact beam in the mold cavity thatreduces interface bonding and reactions between the molten metal and theimpact beam.
 3. The method according to claim 1 wherein the impact beamis made of steel.
 4. The method according to claim 1 wherein providing amolten metal to the mold cavity includes providing a molten aluminumalloy to the mold cavity.
 5. The method according to claim 1 whereinproviding a molten metal to the mold cavity includes providing a moltenmagnesium alloy to the mold cavity.
 6. A method for die casting an innerdoor panel for a vehicle side door, said method comprising: providing adie cast mold including a first mold half and a second mold half eachincluding a cavity that combine to provide a mold cavity, said moldcavity being configured to form the inner door panel; positioning animpact beam in the mold cavity prior to combining the first mold halfand the second mold half, wherein the impact beam is made of steel;providing a molten metal to the mold cavity so that molten metal flowsinto all areas of the mold cavity and around the impact beam after thefirst mold half and the second mold half are combined, wherein providinga molten metal to the mold cavity includes providing a molten aluminumalloy to the mold cavity; and removing a solidified molded inner doorpanel from the die cast mold that includes an encapsulated impact beam.7. The method according to claim 6 further comprising applying a coatingon a surface of the impact beam prior to positioning the impact beam inthe mold cavity that reduces interface bonding and reactions between themolten metal and the impact beam.
 8. A method for die casting an innerdoor panel for a vehicle side door, said method comprising: providing adie cast mold including a first mold half and a second mold half eachincluding a cavity that combine to provide a mold cavity, said moldcavity being configured to form the inner door panel; positioning animpact beam in the mold cavity prior to combining the first mold halfand the second mold half, wherein the impact beam is made of steel;providing a molten metal to the mold cavity so that molten metal flowsinto all areas of the mold cavity and around the impact beam after thefirst mold half and the second mold half are combined, wherein providinga molten metal to the mold cavity includes providing a molten magnesiumalloy to the mold cavity; and removing a solidified molded inner doorpanel from the die cast mold that includes an encapsulated impact beam.9. The method according to claim 8 further comprising applying a coatingon a surface of the impact beam prior to positioning the impact beam inthe mold cavity that reduces interface bonding and reactions between themolten metal and the impact beam.